Air intake BBZ

[YS53]

I will do that but tbh I have never bothered too much with the polo mpg,I do know the 'safe' range on a tankful so I can roughly compare with that

 

rgds baz

[YS53]

Tried out my new 'Torque' app/OBD dongle thingy today and we went for a short (14 mile) drive to get some real time engine parameters - Engine Intake Temp started off at +9 deg c (agreeing with ambient) but was up to + 35 deg c at the halfway point - by the time we got back into town it was reading +42 deg c - so even with the Intake Flap closed - the engine is still getting hot air LOL. 

[Breezy_Pete]

I think that's just what temperature the air in the engine bay is?

Is there actually a duct from the grille that connects into the engine cover, or just this arrangement where it is 'near' the intake?

I have my laptop with me today, so could log some temps on the way home for comparison.

 

Edited 2 April, 2019 by Wino

[sepulchrave]

It would be a helluva lot hotter than that if the flap was stuck sucking air from around the exhaust manifold.

[YS53]

I agree @Wino it does depend where the intake temp sensor is.

My engine bay is exactly like your pic .

I was going to have a look at where the temp sensor is mounted this afternoon.

[YS53]

2 minutes ago, sepulchrave said:

It would be a helluva lot hotter than that if the flap was stuck sucking air from around the exhaust manifold.

 

It would indeed sir 

[Breezy_Pete]

Just now, YS53 said:

where the intake temp sensor is

It's in the same package as the MAP sensor, so (RHD) driver's side of inlet manifold.

[Breezy_Pete]

It occurs to me that it would be fairly easy to DIY a duct that does connect the cold air inlet of the airbox/engine cover to the inside of that bit coming off the grille.

[YS53]

49 minutes ago, Wino said:

 

I have my laptop with me today, so could log some temps on the way home for comparison.

 

 

 

That would be useful

[YS53]

3 minutes ago, Wino said:

It occurs to me that it would be fairly easy to DIY a duct that does connect the cold air inlet of the airbox/engine cover to the inside of that bit coming off the grille.

 

Funny you should say that  I was also thinking maybe of an external blank for the Hot Air Inlet underneath the Engine Cover assy.

[Breezy_Pete]

4 minutes ago, YS53 said:

 

Funny you should say that  I was also thinking maybe of an external blank for the Hot Air Inlet underneath the Engine Cover assy.

 

If the flap is forced to be closed somehow or other, then I don't think that would matter. Not too sure exactly what mine does at the moment, as I replaced the thermostat with one off a Volvo, and never really checked in detail what happened to intake temperatures, so I don't know how closed/open it stays.  Having completely shut the one on the missus's car and seen no problems over this winter, I'll probably do the same with mine.

 

Will happily do some logging on the way home, just need to set a reminder on my phone!

[sepulchrave]

On such a small engine with so little power you won't notice any difference so it really isn't worth the effort, you'll probably just end up using slightly more fuel.

[Breezy_Pete]

The missus's car has never been better on fuel since forcing the flap to full cold.  Long term average over 7 years is about 41.5

This is a plot of how it's been since, I reckon not far off 10% better (8% actually, almost exactly 45mpg over that period):

 

Edited 2 April, 2019 by Wino

[Breezy_Pete]

Logging IAT for the second half of my ten minute commute home in the Polo showed an average of about 45°C.  Definitely room for improvement.  Will screw the flap full 'cold' first, then think about linking the airbox cover to the grille thingy. Thanks for prompting me to look into this again @YS53.

[sepulchrave]

Cold air on port injection engines generally increases fuel consumption due to poorer atomisation and droplet condensation at the boundary layer.

[Breezy_Pete]

Not too interested in general cases if the specific ones I look at show the opposite.

 

[YS53]

2 hours ago, Wino said:

Logging IAT for the second half of my ten minute commute home in the Polo showed an average of about 45°C.  Definitely room for improvement.  Will screw the flap full 'cold' first, then think about linking the airbox cover to the grille thingy. Thanks for prompting me to look into this again @YS53.

 

Hey Don't thank me - thank my Torque app  (great little toy)

I think slightly cooler air for the intake certainly aint a bad thing for the warmish months anyway,I was surprised how quickly the inlet temp came up even at 9 deg ambient.

[YS53]

1 hour ago, sepulchrave said:

Cold air on port injection engines generally increases fuel consumption due to poorer atomisation and droplet condensation at the boundary layer.

 

It would be nice to get the intake air a little colder though I think - maybe circa 20 deg c would be good?

I doubt that would be cold enough to give any atomisation problems - but we would soon see LOL

[sepulchrave]

2 hours ago, Wino said:

Not too interested in general cases if the specific ones I look at show the opposite.

 

 

But you haven't fitted a cold air feed so I'm unclear if you're getting to the heavily serotonin depleted stage of just arguing blindly on principle.

[Breezy_Pete]

Changing the Fabia from failed thermostat fulltime preheated air to fulltime non-heated is what I'm referring to. And without telling the missus, so a blind experiment. 

I only argue with you when you're wrong.

[sepulchrave]

17 hours ago, Wino said:

Changing the Fabia from failed thermostat fulltime preheated air to fulltime non-heated is what I'm referring to. And without telling the missus, so a blind experiment. 

I only argue with you when you're wrong.

 

...or when you misunderstand me.

[Breezy_Pete]

Won't happen again.